Continuous gauge control



Sept. 14, 1965 J. w. BEATTY CONTINUOUS GAUGE CONTROL 3 Sheets-Sheet 1 Filed Oct. 18, 1961 jazz Sept. 14, 1965 J. w. BEATTY 3,205,585

CONTINUOUS GAUGE CONTROL jFigd Oct. 18, 1961 3 Sheets-Sheet 2 La -in. 1;

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444m? fwung v/ United States Patent 3,205,585 CONTINUOUS GAUGE CONTROL John W. 'Beatty, Glen Ellyn, Ill., assignor, by mesne assignments, to Russell V. Leonardson, River Forest, Ill. Filed Oct. 18, 1961, Ser. No. 145,936 1 Claim. (Cl. 33-148) This invention is concerned with a device for continuously gauging the thickness of moving sheet material, and more particularly, with a continuous gauging and control device which automatically inspects sheet stock being fed in strip form into a punch press or other machine, and interrupts power to the machine when the stock being fed is oversize or undersize beyond predetermined acceptable limits.

Earlier devices of this general character have not been wholly satisfactory in that they gauge the marginal edge of the moving strip, which is often of unpredictably varying thickness because of the flow and burring of the metal in the slitting operation by means of which the narrower commercial widths of strip are made from the wider rolls of sheet stock from the rolling mills. Inasmuch as only a center portion of the strip usually becomes the manufactured article, such gauges do not properly reflect the actual thickness of the metal which subsequently becomes the work piece, and, accordingly, are either over-critical of the stock, or fail to detect significant variations in the portions of the stock which are important.

Other devices attempt to gauge over an extended width of strip with the result that the reading is falsely influenced by such twisting of the strip stock as will occur in the gauge, either a constant twist resulting from failure to accurately align the guides which determine the path of the stock from the supply reel to the feeding mechanism, or from the feeding mechanism to the press, whichever point is selected for the gauging, or an occasional momentray twist which may occur in the travelling stock when damaged edge portions of the strip leave the supply reel or enter the feeding or straightening rolls of the feed mechanism.

In still other cases, the construction of the gauging device is such that when the gauge'is opened for the threading of the strip stock, the mechanical parts of the associated relatively sensitive indicator or detector are stressed to such an extent as to be forced out of adjust ment and are subject, after repeated occasions, to permanent damage.

Accordingly, it is the object of the present invention to obviate the aforementioned difficulties in a sturdy gauging device of simple design which will gauge that portion of the stock which becomes the work rather than the scrap, which will accurately gauge the stock for the control of the associated press to interrupt power to the press upon the occurrence of variation in thickness of from .001 to .010 inch in either direction with a tolerance or accuracy not exceeding .0005 inch, whose gauging is unaffected by such twisting of the stock as is of no consequence to the machine being controlled, i.e., of such insignificant character as to fail to damage the dies of the press, and which is so constructed and arranged that its associated indicator and control mechanism is unaffected by the opening of the gauge, either for the initial admission of the stock, or by the occasional occurrence of large and unpredictable obstructions, e.g., welded joints in the coiled strip, or dents or kinks in the stock which inevitably result from the mechanical handling of the stock in roll or coil form.

Other objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings of a preferred embodiment of the invention.

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In the drawings:

FIGURE 1 is a perspective view of a gauging device embodying the invention, viewed from a front quarter;

FIGURE 2 is a perspective view of the device from the opposite quarter, showing the reverse side;

FIGURE 3 is a front elevational view of the gauge device of FIGURES 1 and 2, showing the stock traversing the gauge rolls from right to left;

FIGURE 4 is a rear elevational View, partially cut away and sectioned to better illustrate some of the parts, and showing in dotted lines others which are hidden;

FIGURE 5 is an end elevational view, looking in the direction in which the stock passes through the gauge; and partially broken away and sectioned to better show the gauge roll mountings;

FIGURE 6 is an enlarged fragmentary sectional view taken along the line 66 of FIGURE 5, and illustrating, in particular, the electrical indicator or detector switch by means of which the occurrence of oversize or undersize stock in the gauge becomes effective to interrupt power to the press, as earlier mentioned;

FIGURE 7 is a fragmentary sectional view taken along the line 77 of FIGURE 6;

FIGURES 8 and 9 are fragmentary sectional plan views of the detector switch taken along the lines 88 and 9-9 respectively of FIGURE 7;

FIGURE 10 is an enlarged fragmentary elevational view of the gauge rolls looking into the nip of the rolls, i.e., as seen by the entering stock; and

FIGURE 11 is a diagram of the electrical control circuit by means of which the gauge device may be coupled with the motor starter of the press or, if desired, with any other suitable electrically-operated mechanism for interrupting power, either mechanically or electrically, to the press.

Briefly, in the preferred embodiment, the gauging mechanism which reads the moving stock includes a pair of opposed roll sets, one of which pair is journalled on a fixed axis and the other in the yoke arm of a rock shaft, a second arm of which is engaged in following contact by the spring-biased operator of a double-acting detector switch. A-n auxiliary set of rolls in advance of the gauge rolls guides the stock into the opposed gauge rolls perpendicularly to the common plane of their axes to assure accurate reading.

The arm of the rock shaft engaged by the following switch operator is so arranged that when the gauge rolls are opened to thread the stock between them, the operator arm is completely removed from the operator of the detector switch to remove all strain from the switch and to preserve any pre-existing adjustment. The arrangement of the rolls and their support in a rigid frame is such that only the work portion of the passing stock is measured i.e., the rolls and frame are so constructed that, over a wide range of stock widths, the gauge rolls read on the center or near-center of the advancing stock.

The gauge rolls themselves are of such form that one of them is in straight-line contact with the stock over a substantial intermediate width, and the other is crowned so as to have essentially point or limited area contact with the stock, depending upon the hardness of the stock, thereby to prevent erroneous reading, but nevertheless to reject the stock, i.e., to interrupt the press, upon the occurrence of any deformation beyond the acceptable limits to which the gauge is adjusted.

Referring now to FIGURES 1 to 5 and 10 for a detailed description, the device includes a main frame 20 of heavy construction, either a casting or weldment, having a base portion 22 adapted to be mounted on a suitable bed and to provide support for the lower sets of gauge rolls 24 and guide rolls 26, and an upper portion 28 having therein a cavity 30 (FIG. 5) for certain of the electrical shafts upon which the upper sets of the gauge and guide rolls are mounted. The two frame portions are connected together by a heavy wall plate 32 (FIG. which forms part of both at the back of the device, and are spaced from one another to provide clearance space 34 for the passage of the strip stock between them.

The baase portion 22 is essentially an upwardly open box structure, the floor plate 36 of which has cut therein on its underside a keyway 38 to receive a bar key 40 by means of which the device is positioned on a suitable bed plate 42, and adjustable thereon transversely of the path of the strip stock so as to reach the center of various widths of strip. Front and intermediate walls 44 and 46, braced by enclosing end walls 48, provide a cradle between which the lower gauge rolls 24 and the lower guide rol1s 26 are supported upon fixed shafts 50 and 52 respectively, secured in position by means of set screws 54 in the front wall, as shown in FIGURES 1, 3 and 5,

The upper frameportion 28 includes, in addition to the heavy back plate 32 common to both portions, a heavy bottom plate 56, which together with the back plate and front and side plates'58 and 60, form the housing cavity 30 for certain electrical components. A cover plate 62,, secured in place by suitable screws, closes the cavity to protect the electrical components.

The back plate 32 and the heavy lower plate 56 of the upper frame portion are bored horizontally from frontto-back of the frame adjacent both ends, and the bores thus formed are hushed at each end to provide bearings 64 for the'rock shafts 66 and 68. On the front end of each rock shaft is a yoked rock arm 70 secured to the shaft by means of dowel pins, and supported in the yokes at their outer ends are short shafts 72 upon which the upper sets of gauge rolls 74 and guide rolls 76 are journalled.

Both rock shafts 66 and 68 protrude as well from the back plate 32 of the frame (FIGURES 2, 4 and 5), the

rock shaft 68 which supports the upper guide rolls 76 7 having mounted thereon a downwardly extending rockarm 78 similarly secured to the shaft by a dowel pin, and the rock shaft 66 which supports the upper gauge rolls 74 being provided with a double-arm rock lever 80, one arm of which extends downwardly from the shaft in opposition to the rock-arm 78 of the guide-roll rock shaft 68, and the other arm of which extends upwardly, adjacent a switch housing 82, to serve as an operator for the indicator or detector switch, in a manner later to be described.

The rock arm 78 on the guide-roll rock shaft 68, and the opposed, downwardly-extending arm of the switchoperating rock lever 80 secured to the gauge-roll rock shaft 66,. are each provided near their lower ends with inner and outer wear bolsters 84 which take the form of hardened steel rest buttons, the shanks of which are pressed into drilled holes extending through the arm 78 and lever 80 at right angles to the rock shafts. Mounted by cap screws to the back wall of the frame between the inner bolsters 84 is a bored housing 88 having therein a free-floating compression spring 90 and at each end thereof a metal ball 92 which is forced by the spring into engagement with the inner bolster of the adjacent rockarm. It will beapparent therefore that the spring 90', acting in both directions through the balls 92 upon the bolsters 84 in the rock arms of the shafts, tends to rotate the rock shafts 66 and 68 in opposite directions, and, through the yoke arms 70 at the front of the frame, to force the two movable sets of rolls 74 and 76 into engagement with the lower fixed axis sets 24 and 26.

At each end of the base portion 22 of the frame is a rearwardly projecting lug 94 in which there is mounted a hand screw 96 aligned axially with the compression spring 90, balls 92, and bolsters 84, each such screw having thereon a rounded contact head 98 adapted, when the screw is taken up, to engage the outer bolsters 84, and, by further movement, to move the rock arms 78 and the lower control components and providing bearings for the rock 4 arm of the rock lever 80 toward each other against the action of the spring. It will be equally obvious that the resulting rocking of the shafts separates the two pairs of rolls, as for example, when desired to thread a strip of sheet stock through the nips of the rolls.

The rolls themselves-are mounted, as previously indicated, upon shafts which are fixed respectively in either the cradle of the lower frame portion (shafts 50 and 52), or in the yokes of the two rock arms 70 (shafts 72). Each shaft of each pair of rolls, a pair being taken to mean one set of lower fixed axis rolls and its associated set of upper movable rolls, supports three coaxial individual roll elements which are spaced from one another along the shaft and also from the supporting walls of the lower portion, or from the yoke of the rock arms, as the case may be, by spacing collars 100 (FIG. 5). Each individual roll element is preferably a ball bearing, the inner race of which is mounted on its supporting shaft with a slight drive fit, the outer race serving as the actual roll or strip-contacting portion.

For the sake of accuracy, each of the .ball bearings which constitute the troll elements is carefully selected for a maximum run-out of not more than .0001 inch on the OD.

.These are preferably ground in ganged assembly on the 7 that which is associated with the rock shaft 66, and which,

through the rock-lever operates upon the detector switch, is provided with a crown so as to contact the strip in a point in the mid-plane of that roll. For practical purposes and for most applications, a crown of radius from 1 to 1 /2 inches, depending upon the softness of the stock to be gauged, has been found satisfactory. The flanking outer rolls 104 on the same shaft are ground with flat surfaces, as are all of the other rolls, both gauge and guide rolls, but have an outer diameter which is less than the maximum CD. of the crowned roll 102, and preferably of the order of about .004 inch less.

With the foregoing relationship of the crowned gauge roll to its smaller-diameter flanking rolls, the normal reading of the gauge is limited to that done by the crown roll, so that the strip stock, supported upon the lower fixed axis rolls 24, is actually measured, under normal circumstances, at only one point, or, more specifically, along a straight longitudinal line which will vary in width according to the hardness of the/strip stock and the amount of crown on the gauge roll.

The flanking rolls 104 maintain the stock in essentially untwisted condition as it passes beneath the crowned center roll 102 so as to prevent an otherwise erroneous reading. On the other hand, if the stock should be sufiiciently deformed, it may lift the gauge rocker arm by contact 7 either with the crowned roll or with the flanking rolls, and

operate the detector switch so as to halt the press.

Referring now to FIGURES 4 and 6 to 9 inclusive, it will be noted particularly in FIGURE 4 that the upper arm of therock lever 80 is also provided with a protruding bolster formed, in this instance, as a head 106 or integral part of a micrometer screw 108. The upper end of the lever is split, as seen particularly in FIGURE 2, and any adjustment of the screw 108 in and out of the arm may be maintained by means of a lock screw 110 which, when tightened, squeezes the two parts of the split lever together to lock the adjusting screw in place. The adjusting screw should have a fairly fine thread, about 40 to the inch, for a relatively fine adjustment for purposes later to be described.

Enclosed within the heavy switch housing 82 is the'detector switch 112, a double-throw, single-pole leaf switch comprising three leaves or blades 113, 114, secured in a laminated insulating block 116 of phenolic material by means of bolts 117 to normally maintain the blades in spaced relation. As shown particularly in FIGURES 7 and 9, the shank of the center blade 114 is off-set rearwardly from those of the flanking blades 113 and 115, and the latter are in the form of an inverted L to provide rearwardly-extending upper tab portions, the extremities of which are aligned with the upper end of the center blade 114. As shown in FIGURES 6 and 8, all blades are provided with opposed contact buttons, preferably of silver or platinum.

While all of the three switch blades are permanently secured in fixed spaced relation at their base ends within the mounting block 116, the upper ends of the flanking outer blades 113 and 115 are more accurately positioned by adjusting screws 118 and 119 which extend into the heavy switch housing 82 from the sides thereof. Each such adjusting screw is provided at its end with a ball nose 120 of insulating material, such as a phenolic resin, which is cemented or otherwise secured to the end of the screw. The adjusting screw 118 of the outer blade 113 is preferably adjusted at the factory, and then secured by any suitable means. The opposed adjusting screw 119, which operates upon the other flanking switch blade 115, may similarly be secured in any desired position of adjustment by means of a set screw 122 or the like which bears upon the threads of the adjusting screw 119 through an intermediate plug 124 of relatively soft metal, such as brass, to protect the threads of the adjusting screw. For the sake of reference, the outer blade 113 may be called the undersize blade, and the other outer blade 115 the oversize" blade.

In its position rearwardly of the flanking outer blades, the center blade of the switch is engaged on opposite sides by aligned plungers 126 and 127 slidably mounted on the side walls of the switch housing, each plunger being provided with a rounded nose of insulating material cemented to the metal shank of the plunger. The lefthand or back-up plunger 126, as seen in FIGURE 6, is provided with an integral head 128, and the shank of the plunger, intermediate the head and the inner wall of the switch housing, is surrounded by a compression spring 130 which urges the nose of the plunger into engagement with the center leaf of the switch.

The opposed right-hand or operating plunger 127 extends through the wall of the switch housing and is provided on its outer end with a rounded tip 132 adapted to engage the adjustable bolster 106 on the upper end of the rock lever 80. The associated slide bearing in the housing wall is counterbored from the outside to receive a compression spring 134 which bears against the under side of the outer head 136 of the plunger to maintain the same, within the limits of its movement, in following contact with the bolster 106 on the rock-lever.

The movement of the operating plunger 127 outwardly of the switch housing 82 is limited in any suitable manner as such, for example a snap ring 138 on the shank of the plunger, or a roll pin, adapted to engage the inner wall of the switch housing 82 as the plunger 127 moves outwardly under the force of the aforementioned spring 134. Reverse or inward movement of the operating plunger into the housing is limited by engagement of the underside of the plunger head 136 with the outer wall of the housing which, because of its sturdy construction and attachment to the back wall 32 of the frame, relieves the detector switch of all strain in the event the rolls suddenly close, as for example, when the supply roll is exhausted, or in the event that the hand screws 96 are turned out with no stock in the roll nips. While the clearances shown in the drawings FIGURES 4 and 6 and others are exaggerated for the sake of clarity of illustration of the detector switch mechanism, the reciprocal movement of the operating plunger is preferably limited to between .020 and .030 inch.

As the manner of adjusting the switch for its intended 6 purpose follows more readily with an understanding of the electrical signal circuit, we leave the mechanics of the switch and go to the circuit diagram, FIGURE 11.

In the detector circuit, the field coil 140 of a normallyclosed mercury relay 142 is connected to a source of power 144, represented in the circuit diagram by the fixed mounted male plug (see also FIGURES 2 and 4) in series with a rectifier 146, with the detector switch 112, both outer blades of which are shunted, and with a large resistance 148, sufficient with the rectifier and the field coil of the relay to limit the current flow to the few milliamperes necessary to operate the relay when the detector switch is closed in either direction. A signal lamp 150 is connected in parallel across the relay field coil 140. The relay itself may, for example, be a 5 ampere, magnetically controlled mercury switch commercially available from Mercoid Company.

Accordingly, whenever the detector switch is closed in either direction, the flow of current in the detector circuit opens the mercury relay, simultaneously lighting the signal lamp.

The relay itself is connected through the female receptacle 152 in the upper left-hand portion of FIGURE 11 (see also FIGURES 2 and 4) in series with, for example, the holding circuit of a conventional induction motor starter (not shown) of the controlled machine. Thus, when the detector switch is operated and the relay opened, the holding circuit of the motor starter is interrupted and the contacts in the power circuit to the motor drop open. Those skilled in the art will recognize that, if desired, the relay may also be connected to trip a suitable clutching device, electrical or mechanical, in such older installations as may still employ line shaft power, and further that the relay may be normally open or normally closed depending upon the particular operating circuit.

In order to facilitate testing and adjustment of the gauge device without interrupting the operation of the press, or if it be desired to disable the gauge device for any other reason, a simple toggle switch 154 is shunted across the relay and, when closed, effectively removes the detector circuit from that of the motor control of the press.

Returning now to the adjustment of the detector switch to enable it to perform properly, and referring to FIG- URES 4 and 6 to 9 inclusive, when it is desired to adjust the gauge, the hand screws 96 are turned in to lift the yoke arms and, thus, to separate the rolls. Assuming that the stock be used in the press has a nominal thickness of .010 inch, and that the acceptable tolerance in the thickness of the stock for the desired purpose is .001 inch plus or minus, a feeler gauge of .009 thickness is placed between the gauge rolls, i.e., between the crowned roll 102 and its mating support roll, and the hand screws turned out to bring the rolls into contact with the feeler gauge. This position of the rolls, maintained under the action of the spring 90, is the minimum thickness to be tolerated. The locking screw 110 in the upper end of the rock lever is then loosened and the fine thread adjusting screw 108 is turned in until the bolster 106 has depressed the operating plunger 127 sufficiently to bring the button on the center blade 114 into contact with that of the undersize flanking blade 113, indicated by the burning of the signal light 150. The bolster 106 is then backed off slowly just until the signal light is extinguished, and the locking screw is then tightened to secure the bolster in place. The switch is then adjusted for the minimum thickness which will be tolerated in the feed to the press.

To adjust for the maximum thickness, the hand screws 96 are again turned in to open the rolls, the feeler gauge removed and replaced with one .011 inch thick. The hand screws are again turned out to bring the gauge rolls into contact with the feeler gauge. The operating plunger 127, under the force of its spring 134, has moved out- Wardly from the switch housing 82 a distance proportional to the increased thickness of .002 inch between the gauge rolls, and the center switch blade is causedv to follow by the backup plunger 126 and its associated spring 130. The set screw 122 is loosened and righthand adjusting screw 119 turnedin, moving the oversize flanking switch blade 115 inwardly until the signal light is again lit, whereupon the adjusting screw 119 is then backed-off sufiicientlyto extinqu-ish the light, and the set screw 122 again tightened. With the adjustment thus made, the hand screws 96 are again turned into open the rolls, the feeler gauge removed and the stock threaded between the rolls.

When the press is put into operation and the stock fed through the gauge, any thickness below the minimum of .009 inch, in the example given, is reflected by the Closing of a contact between the center and undersize blades 114 and 113, whereas the passage of any stock into the gauge rolls of greater than .011 inch thickness is, reflected by the closing of the contacts between the center and oversize blades 114 and 115.

Closing in either direction opens .the mercury relay, breaking the holding circuit in the motor starter, and thus interrupts the power to .the press.

With the foregoing arrangement of gauge rolls, the stock is measured in a single narrow line and in that portion of the stock which is actually consumed in the press, i.e., the part which enters the dies to become a productive work part, instead of that portion which becomes scrap. In this way, the measurement is not subject to the false reading occasioned by edged distortions in the stock which are of no significance either from the standpoint of the Work piece itself or of the protection of the dies. More importantly, by making the measurement in a single line, as by the crowned roll in opposition to a flat roll, there are no false readings such as are otherwise occasioned by minor twisting of the stock. Moreover, the relationship of the switch-operating plunger to the switch housing and to the rock lever which it follows, removes all strain from the detector switch (which is necessarily delicate for fine discrimination), during large movement of the rolls, e.g., the opening of the rolls for service and for threading of the stock, or by the closing of the rolls under the force of the roll-biasing spring.

Features of the invention believed new and patentable are set forth in the following claim.

What is claimed is: p In a device for continuously gauging the thickness of a traveling strip, a frame, a pair of opposed rolls, means mounting said rolls on said frame to engage opposite faces of a strip threaded through the nip of said rolls, the mounting means of at least one of said rolls being such as-to permit movement of said one roll toward and away from the other, means tendinglto urge said rolls together to cause them to engage the faces of the strip, and a signal system for registering movement of said rolls toward and away from each other beyond predetermined tolerance limits of said strip, said signal system having a sensing member biased in following contact with the mounting means of said movably-mounted roll in such a manner such that nip-closing movement of said rolls moves said mounting means and said sensing member in a given direction, said mounting means including a bolster engageable with said sensing member and adjustable whereby said signal system maybe caused to register when a predetermined lower tolerance limit of said strip is exceeded, said sensing member including means engageable with a portion of said frame after predetermined movement thereof in said given direction so as to arrest said movement of said mounting means and said mem-. ber, adjustment of said bolster being thereby effective to determine the arresting position of said mounting means.

References Cited by the Examiner UNITED STATES PATENTS 1,303,259 5/19 Danner 33-147 1,963,310 6/34 Nichols 33-147 1,984,837 12/34 Kronenberg 33-147 2,019,741 11/35 Steckel et a1. -1 33-148 2,522,877 9/50 Ladrach 33-147 2,794,258 6/57 Danielsson 33-147 2,858,614 11/58 Schuenemann 33-148 2,897,964 8/59 Foster 33-148 ISAAC LISANN, Primary Examiner.

LOUIS R. PRINCE, ROBERT B. HULL, ROBERT L.

' EVANS, Examiners. 

